Compact orthopedic anti-rotation device

Abstract

Embodiments of the present invention relate to systems, methods, and apparatus for immobilizing and/or securing bone portions. Particularly, at least one embodiment involves a compact anti-rotation device that can secure adjacent bones and/or bone portions in a manner that prevents or limits relative rotational movement thereof.

We claim: 
     
       1. A method of immobilizing and securing adjacent bones, to facilitate healing of the bones or tissue or ligaments connected thereto, the method comprising:
 positioning a first bone and a second, adjacent bone at desired locations relative to each other; 
 inserting a first anchor of a compact anti-rotation device through a first outer surface of the first bone and into the first bone; and 
 inserting a second anchor of the compact anti-rotation device through a second outer surface of the second bone and into the second bone such that the first anchor and the second anchor prevent relative rotation of the first anchor relative to the second anchor along an axis of rotation to less than 1° when the applied torque is approximately 200 N-mm such that the first anchor and the second anchor transfer the applied torque to a torsion bar extending between the first anchor and the second anchor. 
 
     
     
       2. The method as recited in  claim 1 , the compact anti-rotation device having a torsion bar extending between the first anchor and the second anchor, the method further comprising positioning the torsion bar relative to an axis of rotation of the first bone and the second bone. 
     
     
       3. The method as recited in  claim 1 , the method further comprising drilling a first plurality of holes into the first bone and a second plurality of holes into the second bone. 
     
     
       4. The method as recited in  claim 1 , wherein inserting the second anchor of the compact anti-rotation device through a second outer surface of the second bone and into the second bone comprises inserting a second plurality of prongs that define the second anchor into the second bone. 
     
     
       5. The method as recited in  claim 1 , wherein the first bone comprises a scaphoid bone and the second bone comprises a lunate bone. 
     
     
       6. The method as recited in  claim 1 , wherein inserting the first anchor of a compact anti-rotation device through a first outer surface of the first bone and into the first bone comprises inserting a first plurality of prongs that define the first anchor into the first bone. 
     
     
       7. The method as recited in  claim 6 , wherein the first plurality of prongs are inserted at an angle substantially perpendicular to an axis of rotation of a joint defined by the first bone and the second bone. 
     
     
       8. The method as recited in  claim 1 , further comprising inserting at least one elongated inner connector through the first bone and through the second bone, thereby fixing the desired location of the first and second bones relative to each other. 
     
     
       9. The method as recited in  claim 8 , wherein inserting the at least one elongated inner connector through the first bone and through the second bone comprises inserting a first K-wire and a second K-wire through the first and second bones to support the applied torque. 
     
     
       10. The method as recited in  claim 8 , wherein the first bone comprises a scaphoid bone and the second bone comprises a lunate bone and wherein inserting the at least one elongated inner connector through the first bone and through the second bone comprises inserting a first K-wire and a second K-wire through the scaphoid and lunate bones. 
     
     
       11. The method as recited in  claim 8 , wherein inserting the first anchor of a compact anti-rotation device through a first outer surface of the first bone and into the first bone comprises inserting a first plurality of prongs that define the first anchor into the first bone. 
     
     
       12. The method as recited in  claim 11 , wherein the first plurality of prongs are inserted at an angle substantially perpendicular to an axis of rotation of a joint defined by the first and second bones. 
     
     
       13. The method as recited in  claim 8 , wherein inserting the second anchor of the compact anti-rotation device through a second outer surface of the second bone and into the second bone comprises inserting a second plurality of prongs that define the second anchor into the second bone. 
     
     
       14. The method of  claim 1 , wherein the first anchor and the second anchor resist the applied torque of 200 N-mm before at least one of the first bone or the second bone breaks. 
     
     
       15. A method of immobilizing and securing adjacent bones and preventing such bones from relative rotation, to facilitate healing of the bones or tissue or ligaments connected thereto, the method comprising:
 positioning a first bone and a second, adjacent bone at desired locations relative to each other; 
 drilling a first plurality of holes into the first bone and a second plurality of holes into the second bone, the first plurality of holes being approximately parallel and the second plurality of holes being approximately parallel; 
 inserting a first anchor of a compact anti-rotation device through a first outer surface of the first bone and into the first bone, the first anchor having a first plurality of prongs, wherein the first plurality of holes correspond with an angle and depth of the first plurality of prongs and the first plurality of prongs are inserted into the first plurality of holes; and 
 inserting a second anchor of the compact anti-rotation device through a second outer surface of the second bone and into the second bone, the second anchor having a second plurality of prongs, wherein the second plurality of holes correspond with an angle and depth of the second plurality of prongs and the second plurality of prongs are inserted into the second plurality of holes, the compact anti-rotation device having a torsion bar extending between the first anchor and the second anchor. 
 
     
     
       16. The method of  claim 15 , wherein the compact anti-rotation device is formed of a metal alloy. 
     
     
       17. The method of  claim 15 , further comprising, after inserting the compact anti-rotation device, limiting rotation of the first bone and the second bone to less than 1° of rotation about any axis when a torque of approximately 200 N-mm is applied. 
     
     
       18. The method of  claim 15 , wherein the first bone is a scaphoid bone and the second bone is a lunate bone. 
     
     
       19. The method of  claim 15 , wherein the compact anti-rotation device is sufficiently rigid to limit relative displacement of the first bone and the second bone to less than 1 mm along any axis when approximately 50 N is applied. 
     
     
       20. A method of immobilizing and securing adjacent bones and preventing such bones from relative rotation, to facilitate healing of the bones or tissue or ligaments connected thereto, the method comprising:
 positioning a scaphoid bone and a lunate bone at desired locations relative to each other to form a joint; 
 drilling a first plurality of holes into the scaphoid bone and a second plurality of holes into the lunate bone; 
 inserting a first anchor of a compact anti-rotation device through a first outer surface of the scaphoid bone and into the scaphoid bone, wherein the compact anti-rotation device is formed of a metal alloy, the first anchor having a first plurality of prongs, the compact anti-rotation device having a torsion bar extending between the first anchor and a second anchor; 
 positioning the torsion bar approximately parallel to an axis of rotation of the joint; 
 inserting the second anchor of the compact anti-rotation device through a second outer surface of the lunate bone and into the lunate bone, the second anchor having a second plurality of prongs; and 
 applying an applied torque to the scaphoid bone relative to the lunate bone along the axis of rotation of the joint, the compact anti-rotation device limiting relative rotation of the scaphoid bone relative to the lunate bone along the axis of rotation. 
 
     
     
       21. The method of  claim 20 , wherein the compact anti-rotation device limits relative rotation of the scaphoid bone relative to the lunate bone along the axis of rotation to less than 1° when the applied torque is approximately 200 N-mm, wherein the first anchor and the second anchor transfer the applied torque to the torsion bar.